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Related papers: Exploring Multiwavelength AGN Variability with Swi…

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We present our sixth work in a series dedicated to variability studies of active galactic nuclei (AGN) based on the survey of the COSMOS field by the VLT Survey Telescope (VST). Its 54 r-band visits over 3.3 yr and single-visit depth of…

Astrophysics of Galaxies · Physics 2022-08-24 D. De Cicco , F. E. Bauer , M. Paolillo , P. Sánchez-Sáez , W. N. Brandt , F. Vagnetti , G. Pignata , M. Radovich , M. Vaccari

Low luminosity active galactic nuclei (LLAGN) probe accretion physics in the low Eddington regime and can provide additional clues about galaxy evolution. AGN variability is ubiquitous and thus provides a reliable tool for finding AGN. We…

We have observed four low-luminosity active galactic nuclei classified as Type 1 LINERs with the X-ray Telescope (XRT) and the UltraViolet-Optical Telescope (UVOT) onboard Swift, in an attempt to clarify the main powering mechanism of this…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Elena Pian , Patrizia Romano , Dan Maoz , Antonino Cucchiara , Claudio Pagani , Valentina La Parola

We review some practical aspects of measuring the amplitude of variability in `red noise' light curves typical of those from Active Galactic Nuclei (AGN). The quantities commonly used to estimate the variability amplitude in AGN light…

Astrophysics · Physics 2010-04-06 S. Vaughan , R. Edelson , R. S. Warwick , P. Uttley

We study the optical variability of a sample of candidate low-mass (dwarf ang Seyfert) active galactic nuclei (AGNs) using Zwicky Transient Facility g-band light curves. Our sample is compiled from broad-line AGNs in dwarf galaxies reported…

Astrophysics of Galaxies · Physics 2023-04-11 Z. Franklin Wang , Colin J. Burke , Xin Liu , Yue Shen

We conduct an analysis of over 60,000 dwarf galaxies (7<=log(M_*/M_\odot)<=10) in search of photometric variability indicative of active galactic nuclei (AGNs). Using data from the Young Supernova Experiment (YSE), a time domain survey on…

The variability of active galactic nuclei (AGNs) is ubiquitous but has not yet been understood. Measuring the optical variation properties of AGNs, such as variation timescale and amplitude, and then correlating them with their fundamental…

Astrophysics of Galaxies · Physics 2024-01-11 Xu-Fan Hu , Zhen-Yi Cai , Jun-Xian Wang

An empirical forward-modeling framework is developed to interpret the multiwavelength properties of Active Galactic Nuclei (AGN) and provide insights into the overlap and incompleteness of samples selected at different parts of the…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Antonis Georgakakis , Angel Ruiz , Stephanie M. LaMassa

We present the multi-wavelength and environmental properties of 37 variability-selected active galactic nuclei (AGNs), including 30 low luminosity AGNs (LLAGNs), using a high cadence time-domain survey (ASAS-SN) from a spectroscopic sample…

Astrophysics of Galaxies · Physics 2025-01-30 Heechan Yuk , Xinyu Dai , Marko Mićić

We present a new method to predict the line-of-sight column density (NH) values of active galactic nuclei (AGN) based on mid-infrared (MIR), soft, and hard X-ray data. We developed a multiple linear regression machine learning algorithm…

Astrophysics of Galaxies · Physics 2023-07-05 Ross Silver , Núria Torres-Alba , Xiurui Zhao , Stefano Marchesi , Andrealuna Pizzetti , Isaiah Cox , Marco Ajello

AGN variability offers a direct probe of accretion physics, disk structure, and black hole growth, but progress has been limited by sample size, cadence heterogeneity, and photometric systematics. The Vera C. Rubin Observatory Legacy Survey…

X-ray variability is a well-established characteristic of active galactic nuclei (AGN), known to correlate inversely with both the supermassive black hole mass and luminosity, although the degree of each remains a topic of debate. The…

One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among the AGN family and…

High Energy Astrophysical Phenomena · Physics 2015-06-15 L. Hernández-García , O. González-Martín , I. Márquez , J. Masegosa

The goal of this work is to search for Active Galactic Nuclei (AGN) in the Galactic disc at very low latitudes with |b| $<$ 2$^\circ$. For this, we studied the five sources from the VVV near-infrared galaxy catalogue that have also WISE…

We analyze 168 Swift monitoring observations of the nearest broad absorption line quasar Mrk 231 in the UV and X-ray bands, where we detect significant variability in the UV ($\sim$2246\AA) light curve with a null probability of…

Astrophysics of Galaxies · Physics 2018-08-29 Lilan Yang , Xinyu Dai , Youjun Lu , Zong-Hong Zhu , Francesco Shankar

The unified model of active galactic nuclei (AGN) includes a toroidal obscuring structure to explain the differences between Type I and Type II AGN as an effect of inclination angle. This toroidal structure is thought to be 'clumpy' as the…

Astrophysics of Galaxies · Physics 2023-01-19 Isaiah Cox , Nuria Torres-Alba , Stefano Marchesi , Xiurui Zhao , Marco Ajello , Andrealuna Pizzetti , Ross Silver

Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled $\sim$200-350 times in 0.3-10 keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation analysis of these datasets yields three…

We combine data from two all-sky surveys in order to study the connection between the infrared and hard X-ray (>10keV) properties for local active galactic nuclei (AGN). The Swift/Burst Alert Telescope all-sky survey provides an unbiased,…

We present a systematic investigation of extremely X-ray variable active galactic nuclei (AGNs) in the $\approx 5.3~{\rm deg}^2$ XMM-SERVS XMM-LSS region. Eight variable AGNs are identified with rest-frame 2 keV flux density variability…

Astrophysics of Galaxies · Physics 2025-03-03 Zijian Zhang , Bin Luo , Linhua Jiang , W. N. Brandt , Jian Huang , Qingling Ni

We report the discovery of a rare new form of long-term radio variability in the light-curves of active galaxies (AG) --- Symmetric Achromatic Variability (SAV) --- a pair of opposed and strongly skewed peaks in the radio flux density…

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